The 100S is the guitar version, and the 200S is the bass version of the amp. They are very close being identical; the differences are in the tone stack. The 100S has a contour knob which is like a high-mid control, and the 200S has "lo" and "hi" boost switches.
Technically, all heads are fine for bass or guitar, but the various names were meant to differentiate between head/cabinet pairings, so in a few situations, a guitar and bass head are the same build, just labelled differently.
I'm not aware of any guitar/bass amps that are identical except for badging, but there are different bass amps (as well as guitar amps) that are identical with different names because of the speaker configuration.
As far as bass specifics amps go from that era, the 200S, Sorado and Sonic II bass amps are the same (KT88/6550), Sonaro, Sonic, and the Sonic I40 bass amps are the same (EL34).
I agree that it doesn't make a lot of difference, the guitar amps work just fine for bass. Apparently Entwistle thought so anyway, and that's certainly good enough for me! It sure looks like a 100S and a pair of 200S cabs to me in this pic.
It’s been a while, but I used to use a Ric 4003 running the bridge PU to a 100S into a D140 loaded 200S cab, and the neck PU to a 200S into a 215S cab loaded with EVM’s. Pretty outstanding tonally IMO.
Ok, what is the output ohmage for these? 16? 8? Dont know where I could find a 16ohm bass cab! Hopefully its an 8...
It’s either wired for 16 & 8 ohms, or for 8 & 4 ohms. The amps have 16, 8 and 4 ohm taps on the output transformer; you can wire them however you need to.
Use the handy search function to find out more. This has been discussed ad infinitum on this forum.
